Container base constructions and methods of making the same

ABSTRACT

Disclosed are container base constructions and methods of making the same. Such container are adapted and configured to reduce or eliminate deformation of the base and/or sidewall when the container is filled and/or stacked. The containers have a sidewall that has a top end and a bottom end; and a base attached to the bottom end of the sidewall. The base of the container includes a center panel which is positioned above the bottom end of the sidewall and an outer convex section. In certain constructions, the center panel is flat. Alternatively, the center panel can be curved (e.g., convex).

FIELD OF THE INVENTION

The present disclosure is directed to container base constructions andmethods of making the same, and more particularly to, containers thathave a base which is adapted and configured to reduce or eliminatedeformation of the base and/or sidewall when the container is filledand/or stacked.

BACKGROUND OF THE INVENTION

When a thermoplastic container or cup is filled with a product,typically a liquid, and then sealed, internal pressure can be createdwithin the container. As a result, the base and/or sidewall of thecontainer often bulge/deform. This is particularly a problem when thewalls of the cup are thin, or otherwise not sufficiently rigid toprevent the bulging or deformation. This is increasingly the case asmanufacturing targets require minimal use of material or where the aimis to reduce the overall weight of the container. This deformationresults in a number of possible problems, including altering theappearance of the container to the point that consumers may not purchaseor would otherwise return a product in a container with bulging ordeformed walls. Furthermore, when such containers are to be stacked onstore shelves, for example, bulging may have a negative impact on thestackability of the containers.

As is known in the art, it is possible to mitigate some of the effectsof bulging by designing containers with thicker walls, or incorporatingother strengthening or structural elements into the container walls.However, these solutions are not always possible or can lead toincreased material costs, container weight and other manufacturingand/or design inefficiencies.

There is a need therefore, for container base constructions and methodsof making the same, and more particularly to, containers that have abase which is adapted and configured to reduce or eliminate deformationof the base and/or sidewall when the container is filled and/or stacked.

SUMMARY OF THE INVENTION

The purpose and advantages of the below described illustratedembodiments will be set forth in and apparent from the description thatfollows. Additional advantages of the illustrated embodiments will berealized and attained by the containers and methods particularly pointedout in the written description and the claims herein, as well as fromthe drawings.

To achieve these and other advantages and in accordance with the purposeof the illustrated embodiments, in one embodiment, described herein is acontainer that includes a sidewall that has a top end and a bottom end;and a base attached to the bottom end of the sidewall. A cavity isbounded by or defined by the sidewall and the base. The base of thecontainer includes a center panel which is positioned above the bottomend of the sidewall and an outer convex section. In certainconstructions, the center panel is flat. Alternatively, the center panelcan be convex.

In embodiments of the present disclosure, an inner panel connects thecenter panel to the outer convex section of the base. It is envisionedthat in constructions wherein the container is round, the inner panelcan be ring-shaped. In such constructions, a cross-section taken throughthe sidewall is circular and defines a longitudinal axis for thecontainer. Moreover, in such embodiments the base has a cross sectionthat is axially symmetrical.

It is envisioned that the container can further include a lid whichengages with the sidewall to form a leak resistant or proof seal.Moreover, the container can also include a hinge joining the lid to thesidewall of the container.

In certain embodiments, a material thickness is the same for the lid,sidewall and base. In such constructions, the base, sidewall, lid andhinge can be formed from a single sheet of material. However, in certainconstructions the thickness of the lid, sidewall and base can vary. Forexample, it could be advantageous to form the lid using a thinnermaterial. It is envisioned that the material used to form the containercan be a polymer and the container can be thermoformed from a singlesheet of material.

It is also envisioned that in certain embodiments, the sidewall isformed at an angle greater than 90 degrees with respect to the baseand/or the surface upon which the container will rest.

Preferably, the deflection of the center panel of the base does notexceed 0.029 inches when the container is fully loaded.

The present disclosure is also directed to a further containerembodiment that includes a sidewall having a top end and a bottom end;and a base attached to the bottom end of the sidewall and defining acavity bounded by the sidewall and the base. In such a construction, thebase includes a flat center panel and an outer convex section. Thecenter panel is positioned above the bottom end of the sidewall.

The present disclosure is further directed to a container embodimentthat includes a sidewall that has a top end and a bottom end; and a baseattached to the bottom end of the sidewall. The base and the sidewallcooperate to define a cavity. In this embodiment, the base includes aconvex center panel and an outer convex section, wherein the convexcenter panel is positioned above the bottom end of the sidewall.

The present disclosure is further directed to a container that includesa sidewall having a top end and a bottom end; and a base attached to thebottom end of the sidewall. A cavity is defined by the sidewall and thebase. In this embodiment, the base includes a flat center panel and anouter convex section, wherein the center panel is positioned above thebottom end of the sidewall and is joined to the outer convex sectionthrough an inner ring panel.

Still further, the present disclosure is directed to a method of forminga container that includes the steps of: forming a lid from a portion ofa single sheet of at least partially transparent plastic material;forming a sidewall from a second portion of the single sheet of at leastpartially transparent plastic material, the sidewall having a top endand a bottom end; and forming a base from a third portion of the singlesheet of at least partially transparent plastic material, the base beingattached to the bottom end of the sidewall defining a cavity bounded bythe sidewall and the base, the base including a center panel and anouter convex section, wherein the center panel is positioned above thebottom end of the sidewall. In certain embodiments, the single sheet ofat least partially transparent plastic material is entirely transparent.

It is envisioned that the center panel can be flat, convex or concave.Moreover, in certain embodiments, an inner panel connects the centerpanel to the outer convex section of the base. Preferably, in roundcontainers, the inner panel is ring-shaped. Additionally, the sidewallhas a circular cross-section and defines a longitudinal axis for thecontainer and the base has a cross section that is axially symmetrical.

Preferably, the lid is formed so as to engage with the top end of theside wall and form a leak resistant or leak proof seal. Additionally,the disclosed method can further include the step of forming a hingethat joins the lid to the sidewall of the container from the singlesheet of plastic material. Preferably, in certain constructions at leastone line of weakness is formed in the hinge. In is envisioned that thesingle sheet of plastic material can have a uniform material thicknesssuch that the lid, sidewall and base each are formed having the samethickness.

The disclosed method can further include the step of forming thesidewall at an angle greater than 90 degrees with respect to the base.It is envisioned that the step of forming the sidewall further includesforming an upwardly projecting bead at the top end of the sidewall whichextends substantially about the perimeter of the container and isconfigured to substantially surround a peripheral edge of the lid andhinder access to the container when the container is closed.

The disclosed method can further include the step of forming vents inthe container to promote airflow therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art, to which the presentembodiments pertain, will more readily understand how to manufacture thenovel containers and employ the novel methods, certain illustratedembodiments thereof will be described in detail herein-below withreference to the drawings, wherein:

FIG. 1A is a perspective view of a container which has been constructedin accordance with an embodiment of the present disclosure showing thecontainer in the open position;

FIG. 1B is a perspective view of the container of FIG. 1A shown in theclosed position;

FIGS. 2A-B provide a top plan view and elevational view of the opencontainer of FIG. 1A;

FIGS. 3A-B provide a top plan view and elevational view of the closedcontainer of FIG. 1B;

FIG. 4 provides a cross-section of the base of a prior art container;

FIG. 5 provides a cross-section of the base of a container which hasbeen constructed in accordance with an embodiment of the presentdisclosure and includes a flat center panel, an inner ring panel and anouter convex section;

FIG. 6 provides a cross-section of the base of a container which hasbeen constructed in accordance with a further embodiment of the presentdisclosure and includes a convex center panel and an outer convexsection;

FIG. 7 provides a cross-section of the base of a container which hasbeen constructed in accordance with yet a further embodiment of thepresent disclosure and includes a flat center panel and an outer convexsection;

FIGS. 8A-8B illustrate the test setup for determining the deflection ofthe bottom panel of a loaded container;

FIG. 9 provides a boxplot graphical illustration of the amount ofdeflection of the center panel for four container embodiments.

FIG. 10 provides a boxplot graphical illustration of the amount liftdeflection occurring around the bottom edge of the sidewall of fourcontainer embodiments; and

FIG. 11 provides a boxplot graphical illustration of the amount liftdeflection occurring around the bottom edge of the sidewall of fourcontainer embodiments for a double stack of containers.

These and other aspects of the subject invention will become morereadily apparent to those having ordinary skill in the art from thefollowing detailed description of the invention taken in conjunctionwith the drawings.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The below illustrated embodiments are directed to container baseconstructions and methods of making the same, and more particularly to,containers that have a base which is constructed to reduce or eliminatedeformation of the base and/or sidewall when the container is filledand/or stacked during shipment and retail. It is to be appreciated thebelow illustrated embodiments are not limited in any way to what isshown, as the illustrated embodiments described below are merelyexemplary of the invention, which can be embodied in various forms, asappreciated by one skilled in the art. Therefore, it is to be understoodthat any structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative for teaching one skilled in the art to variously employthe certain illustrated embodiments.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art relating to the below illustrated embodiments. Although anymethods and materials similar or equivalent to those described hereincan also be used in the practice or testing of the below illustratedembodiments, exemplary methods and materials are now described.

Referring now to FIGS. 1A-1B, 2A-2B and 3A-3B, there is illustrated acontainer which has been constructed in accordance with an embodiment ofthe present invention that has been designated as reference numeral 100.Container 100 is a round cup but those skilled in the art will readilyappreciated that other size and shape containers, vessels, etc. can beused without departing from the scope of the present disclosure.

Container 100 includes a sidewall 20 that has a top end 24 and a bottomend 22. A base 40 is attached to the bottom end 22 of the sidewall 20. Acavity 50 is bounded by or defined by the sidewall 20 and the base 40.As shown in FIGS. 2B and 3B, the sidewall 20 of container 100 is formedat an angle α that is greater than 90 degrees with respect to the base40 or surface upon which the container will rest.

The container 100 further includes a lid 60. Lid 60 includes a flatcenter panel 62 which is surrounded by a peripheral sealing surface 64.The top end 24 of the sidewall includes an upper peripheral rim 26 and asealing surface 28 (see FIG. 2B) which engages with a sealing surface 64associated with the lid 60 to form a leak resistant seal.

In the embodiment shown in FIGS. 1A-3B, container 100 also includes ahinge 70 joining the lid 60 to the sidewall 20 of the container 100. Asa result, container 100 is a single piece construction. However, thoseskilled in the art will appreciate that container 100 could be atwo-piece construction without departing from the scope of the presentinvention. Moreover, containers constructed in accordance with theteachings of this disclosure do not need a lid and may simply include afoil cover or some other type of closure mechanism.

Referring now to FIGS. 4-7 which illustrate various base constructionswhich can be used with container 100. FIG. 4 illustrates a prior artbase construction which is referred to as base 140. As shown in thisfigure, base 140 includes a raised, flat center panel 142, an angledinner panel 144 and a flat outer panel 146 which would sit flat upon thesupporting surface. The inventors of the present invention have learnedthrough experience that containers which have been constructed to have abase as shown in FIG. 4 tend to deform or bulge when fully loaded. Itwas determined that the flat outer panel 146 acted as a lever whichfacilitated deformation of the base and sidewall when the container wasloaded. More specifically, as will be described in detail below, whenthe container is loaded the weight of the product will cause the centerpanel 142 to deflect downward which in turn causes the outer edge 148 ofthe base 140 to lift off the supporting surface. This makes thecontainer particularly unsuitable for stacking.

Referring now to FIGS. 5-7 which illustrates three base embodimentswhich have been constructed in accordance with the present invention andhave been identified using reference numerals 240, 340 and 440,respectively.

As shown in FIG. 5, base 240 includes a flat center panel 242, an innerring panel 244 and an outer convex panel 246. As can be readily seen, asmooth, radiused transition is made between the center panel 242 andinner ring panel 244 and the outer convex panel 246. In each of thedisclosed embodiments, the base 240/340/440 of the container 100includes a center panel 242/342/442 which is positioned above the bottomend 22 of the sidewall 20 and an outer convex section 246/346/446.

As shown in FIG. 6, base 340 includes a convex center panel 342 and anouter convex panel 346. As can be readily seen, a smooth, radiusedtransition is made between the center panel 342 and the outer convexpanel 346.

As shown in FIG. 7, base 440 includes a flat center panel 442 and anouter convex panel 446. As can be readily seen, a smooth, radiusedtransition is made between the center panel 442 and the outer convexpanel 446.

The above described constructions illustrate round containers or cupsand in such embodiments, the inner panel and out convex panel arering-shaped. However, as noted about the container does not need to beround and could be other shapes, such as square or oval.

Referring now to FIGS. 8A and 8B which illustrate a bench test set-upfor determining the deflection of the base center panel when thecontainer is loaded. An exemplary testing procedure can be summarized asfollows:

1. Place an empty container into the test fixture;

2. Zero out the dial indicator;

3. Pour 2 lbs of water into the container; and

4. Record the measurement on the dial indicator.

The prior art container of FIG. 4 and each of the containers shown inFIGS. 5-7 where tested. The results obtained for the three baseembodiments were as follows:

Deflection Under 2 Lbs of H2O in Inches Sample # Base 440 Base 240 Base340 1 0.03 0.028 0.02 2 0.029 0.029 0.021 3 0.029 0.026 0.02 4 0.0290.028 0.019 5 0.026 0.024 0.018 6 0.0255 0.024 0.0185 7 0.0235 0.0250.016 8 0.024 0.026 0.018 9 0.023 0.028 0.017 Ave. 0.027 0.026 0.017

This data was converted into a BOX PLOT which is shown in FIG. 9. FIG. 9also includes the data from prior art base 140. The data readilyillustrates that the prior art base 140 exhibited the largest amount ofdeflection as compared to the others. Worth noting is the fact that theprior art container that was tested had a material thickness of 51.2 milwhile the containers having base constructions 240, 340 and 440 had amaterial thickness of only 45.3 mil. Of the three base constructions,base 340 performed the best.

The deflection occurring at the bottom of the sidewall was also measuredfor these same four containers constructions and data representing thedeflection in a single stack of containers and a double stack ofcontainers is shown in the BOX PLOTS provided in FIGS. 10 and 11respectively. As shown therein, the containers having base constructions240, 340 and 440 did not exhibit any lift at the bottom of the sidewallor lift off of the supporting surface while that prior art base design140 despite being a thicker gauge container lifted significantly.

As shown in the figures, each of the containers described hereinincludes tamper resistant and tamper evident features. These featuresare similar to those described in U.S. Pat. Nos. 7,073,680; 7,118,003;8,795,580; 9,132,942 and 9,527,640 which are herein incorporated byreference to the extend they do not conflict with the presentdisclosure.

Still further, an exemplary method for constructing the previouslydescribed containers of the present disclosure can include the followingsteps the order of which can vary:

1. Forming a lid from a portion of a single sheet of at least partiallytransparent plastic material;

2. Forming a sidewall from a second portion of the single sheet of atleast partially transparent plastic material, the sidewall having a topend and a bottom end; and

3. Forming a base from a third portion of the single sheet of at leastpartially transparent plastic material, the base being attached to thebottom end of the sidewall defining a cavity bounded by the sidewall andthe base, the base including a center panel and an outer convex section,the center panel being positioned above the bottom end of the sidewall.

The method can further include the step of forming a hinge that joinsthe lid to the sidewall of the container from the single sheet ofplastic material. Preferably, the single sheet of plastic material has auniform material thickness such that the lid, sidewall and base each areformed having the same thickness. The disclosed method can furtherinclude the steps of: forming the sidewall at an angle greater than 90degrees with respect to the base and forming vents in the container topromote airflow therethrough.

The techniques described herein are exemplary, and should not beconstrued as implying any particular limitation on the presentdisclosure. It should be understood that various alternatives,combinations and modifications could be devised by those skilled in theart. For example, steps associated with the processes described hereincan be performed in any order, unless otherwise specified or dictated bythe steps themselves. The present disclosure is intended to embrace allsuch alternatives, modifications and variances that fall within thescope of the appended claims.

The terms “comprise”, “include”, and conjugations thereof are to beinterpreted as specifying the presence of the stated features, integers,steps or components, but not precluding the presence of one or moreother features, integers, steps or components or groups thereof.

Although the containers and methods of the subject invention have beendescribed with respect to the embodiments disclosed above, those skilledin the art will readily appreciate that changes and modifications may bemade thereto without departing from the spirit and scope of the subjectinvention as defined by the appended claims.

1. A container comprising: a frustoconical sidewall having a top end anda bottom end; and a base attached to the bottom end of the sidewalldefining a cavity bounded by the sidewall and the base, the baseincluding a center panel and an outer convex section, the center panelbeing positioned above the bottom end of the sidewall, wherein the outerconvex section arcuately projects from the bottom end of the sidewallinwardly and upwardly, wherein the bottom end of the sidewall defines abottom plane of the container and the sidewall extends radially outwardat an angle greater than 90 degrees with respect to the bottom plane. 2.The container as recited in claim 1, wherein the center panel is flat.3. The container as recited in claim 1, wherein the center panel isconvex.
 4. The container as recited in claim 1, wherein an inner panelconnects the center panel to the outer convex section of the base. 5.The container as recited in claim 4, wherein the inner panel isring-shaped.
 6. The container as recited in claim 1, wherein thesidewall is cylindrical and defines a longitudinal axis for thecontainer and the base has a cross section that is axially symmetrical.7. The container as recited in claim 1, further comprising a lid whichengages with the sidewall to form a leak resistant seal.
 8. Thecontainer as recited in claim 7, further comprising a hinge joining thelid to the sidewall of the container.
 9. The container as recited inclaim 1, wherein a material thickness is different for the lid, sidewalland base.
 10. The container as recited in claim 1, wherein the sidewallis formed at an angle greater than 90 degrees with respect to a surfaceupon which the container will rest.
 11. The container as recited inclaim 1, wherein the base, sidewall, lid and hinge are formed from asingle sheet of material.
 12. The container as recited in claim 1,wherein a deflection of the center panel of the base does not exceed0.029 inches when the container is fully loaded.
 13. The container asrecited in claim 1, wherein the container is made from a thermoformedpolymer.
 14. A container comprising: a frustoconical sidewall having atop end and a bottom end; and a base attached to the bottom end of thesidewall defining a cavity bounded by the sidewall and the base, thebase including a flat center panel and an outer convex section, thecenter panel being positioned above the bottom end of the sidewall,wherein the outer convex section arcuately projects from the bottom endof the sidewall inwardly and upwardly, wherein the bottom end of thesidewall defines a bottom plane of the container and the sidewallextends at an angle greater than 90 degrees with respect to the bottomplane.
 15. A container comprising: a frustoconical sidewall having a topend and a bottom end; and a base attached to the bottom end of thesidewall defining a cavity bounded by the sidewall and the base, thebase including a convex center panel and an outer convex section, theconvex center panel being positioned above the bottom end of thesidewall, wherein the outer convex section arcuately projects from thebottom end of the sidewall inwardly and upwardly, wherein the bottom endof the sidewall defines a bottom plane of the container and the sidewallextends at an angle greater than 90 degrees with respect to the bottomplane.
 16. A container comprising: a frustoconical sidewall having a topend and a bottom end; and a base attached to the bottom end of thesidewall defining a cavity bounded by the sidewall and the base, thebase including a flat center panel and an outer convex section, thecenter panel being positioned above the bottom end of the sidewall andjoined to the outer convex section through an inner ring panel, whereinthe outer convex section arcuately projects from the bottom end of thesidewall inwardly and upwardly, wherein the bottom end of the sidewalldefines a bottom plane of the container and the sidewall extends at anangle greater than 90 degrees with respect to the bottom plane.